1. Field of the Invention
This invention relates to a method for stamping a monofilament of synthetic resin for slide fastener coupling elements, and more particularly to a stamping method for continuously providing on the monofilament coupling head portions, leg turnover portions, deformed portions facilitating bending, grooves receptive of sewing threads, etc. of slide fastener coupling elements.
2. Description of the Related Art
A method for stamping a monofilament of synthetic resin for slide fastener coupling element is known from, for example, Japanese Patent Publications 24347/1969 and 8902/1988. In the known method, as shown in FIG. 12 of the accompanying drawings, a monofilament E is continuously stamped by a pair of rotating rollers A, B having circumferential stamping teeth projections C, D as the monofilament E is supplied between the two rollers A, B.
However, in this prior art method, since the stamping teeth bite into the monofilament abruptly, cracks tend to develop in shaped portions. And since the molding teeth are separated from the monofilament suddenly after having compressed the monofilament, the pressing time is not sufficient to cure the individual shaped portion in a correct contour. Therefore it is difficult to obtain the shaped portions always with accuracy.